Editing Ring system (section)

==Rings systems of minor planets and moons==
Reports in March 2008 suggested that Saturn's moon [[Rhea (moon)|Rhea]] may have [[Rings of Rhea|its own tenuous ring system]], which would make it the only moon known to have a ring system.<ref name="NASArhea"/><ref name="Jones_2008"/><ref name="LakdawallaE"/> A later study published in 2010 revealed that imaging of Rhea by the [[Cassini–Huygens|''Cassini'' spacecraft]] was inconsistent with the predicted properties of the rings, suggesting that some other mechanism is responsible for the magnetic effects that had led to the ring hypothesis.<ref name="tiscareno2010"/>

Prior to the arrival of ''[[New Horizons]]'', some astronomers hypothesized that [[Pluto]] and [[Charon (moon)|Charon]] might have a circumbinary ring system created from dust ejected off of Pluto's small outer moons in impacts. A dust ring would have posed a considerable risk to the ''New Horizons'' spacecraft.<ref name="Steffl 2006"/> However, this possibility was ruled out when ''New Horizons'' failed to detect any dust rings around Pluto.

===Chariklo===
{{main|Rings of Chariklo}}
[[10199 Chariklo]], a [[Centaur (minor planet)|centaur]], was the first minor planet discovered to have rings. It has [[Rings of Chariklo|two rings]], perhaps due to a collision that caused a chain of debris to orbit it. The rings were discovered when astronomers observed Chariklo passing in front of the star UCAC4 248-108672 on June 3, 2013 from seven locations in South America. While watching, they saw two dips in the star's apparent brightness just before and after the occultation. Because this event was observed at multiple locations, the conclusion that the dip in brightness was in fact due to rings is unanimously the leading hypothesis. The observations revealed what is likely a {{convert|19|km|mi|adj=on|abbr=off|sp=us}}-wide ring system that is about 1,000 times closer than the Moon is to Earth. In addition, astronomers suspect there could be a moon orbiting amidst the ring debris. If these rings are the leftovers of a collision as astronomers suspect, this would give fodder to the idea that moons (such as the Moon) form through collisions of smaller bits of material. Chariklo's rings have not been officially named, but the discoverers have nicknamed them Oiapoque and Chuí, after two rivers near the northern and southern ends of Brazil.<ref name="UTchariklo"/>

===Chiron===
{{main|Rings of Chiron}}
A second centaur, [[2060 Chiron]], has a constantly evolving disk of rings.<ref name="Lakdawalla2015"/><ref name = "Ortiz2015"/><ref name="Sickafoose2023"/> Based on stellar-occultation data that were initially interpreted as resulting from jets associated with Chiron's comet-like activity, the rings are proposed to be {{val|324|10|u=km}} in radius, though their evolution does change the radius somewhat. Their changing appearance at different viewing angles can explain the long-term variation in Chiron's brightness over time.<ref name = "Ortiz2015"/> Chiron's rings are suspected to be maintained by orbiting material ejected during seasonal outbursts, as a third partial ring detected in 2018 had become a full ring by 2022, with an outburst in between in 2021.<ref name="Ortiz2023"/>

===Haumea===
{{main|Rings of Haumea}}
[[File:Haumea with rings (37641832331).jpg|thumb|Artist's depiction of Haumea's ring system]]
A ring around [[Haumea]], a [[dwarf planet]] and [[Resonant trans-Neptunian object|resonant Kuiper belt member]], was revealed by a stellar occultation observed on 21 January 2017. This makes it the first [[trans-Neptunian object]] found to have a ring system.<ref name="Sickafoose2017"/><ref name="Ortiz2017"/> The ring has a radius of about {{val|2287|u=km|fmt=commas}}, a width of ≈{{val|70|u=km}} and an opacity of 0.5.<ref name="Ortiz2017"/> The ring plane coincides with Haumea's equator and the orbit of its larger, outer moon [[Moons of Haumea|Hi’iaka]]<ref name="Ortiz2017"/> (which has a semimajor axis of ≈{{val|25657|u=km|fmt=commas}}). The ring is close to the 3:1 [[orbital resonance|resonance]] with Haumea's rotation, which is located at a radius of {{val|2285|8|u=km|fmt=commas}}.<ref name="Ortiz2017"/> It is well within Haumea's [[Roche limit]], which would lie at a radius of about {{val|4400|u=km|fmt=commas}} if Haumea were spherical (being nonspherical pushes the limit out farther).<ref name="Ortiz2017"/>

=== Quaoar ===
{{main|Rings of Quaoar}}
[[File:Quaoar-Weywot_orbit_diagram_projected.png|thumb|upright=1.2|A diagram of Quaoar, its moon [[Weywot (moon)|Weywot]], and its two known rings.]]
In 2023, astronomers announced the discovery of a widely separated ring around the dwarf planet and Kuiper belt object [[50000 Quaoar|Quaoar]].<ref name="Devlin"/><ref name="morgado2023"/> Further analysis of the occultation data uncovered a second inner, fainter ring.<ref name="Pereira2023">{{Cite Q|Q117802048|display-authors=1}}</ref>

Both rings display unusual properties. The outer ring orbits at a distance of {{val|4057|6|u=km|fmt=commas}}, approximately 7.5 times the radius of Quaoar and more than double the distance of its Roche limit. The inner ring orbits at a distance of {{val|2520|20|u=km|fmt=commas}}, approximately 4.6 times the radius of Quaoar and also beyond its Roche limit.<ref name="Pereira2023"/> The outer ring appears to be inhomogeneous, containing a thin, dense section as well as a broader, more diffuse section.<ref name="morgado2023"/>